Method and apparatus for purifying oil in tin coating machines



Jan. 7, 1936.

w. E. TAYLOR 2,026,598 METHOD AND APPARATUS FOR PURIFYING OIL IN TIN COATING MACHINES Filed July 27, 1929 2 Sheets-Sheet 1 INVENTOR ATTORNEY Jan. 7, 1936. w. E. TAYLOR 2,026,598

METHOD AND APPARATUS FOR PURIFYING OIL IN TIN COATING MACHINES Filed July 27, 1929 2 Sheets-Sheet 2 Patented Ja 7, 1936 UNITED STATES METHOD AND APPARATUS FOR PURIFYING OIL IN TIN COATING MACHINES WillianiE. Taylor; East Orange, 'N. J assignor to American Can Company, New York, N. Y., a

corporation of New Jersey- --Application July 27, 1929, Serial No. 381,659

10 Claims.

This invention relates in general to the art of coating iron sheets with tin, and more specifically to an improved and novelmethod for removing impurities from' palm oil which is used in *tin coating machines.

An important object of my invention is the provision of a new and improved method for removing from palm oil or other suitable oil used in tin coating machines, impurities such as scruff or iron-tin alloy -particles, scale, rust, dirt, grit,

dried flux, and'other foreign matter which result from the coating operation, and which, if not removed, interfere with the proper coating of the sheet metal and cause pin holes, black spots, and 5 other undesirable imperfections in tin plate.

Another object of my invention is the provision of an improved method for removing the impurities from the oil used in tinning machines and is especially adapted to tinning machines which produce tin plate for the making of sheet metal containers. v

Another object of the invention is the provision of an apparatus of simple construction and certain operation and adapted to be operated in the practice of my improved method.

Still another object of my invention is the provision of an improved, simple, inexpensive method of purifying oil used in coating machines, which method is adapted to maintain a constant circulation of purified or filtered oil in the tinning machines while they are in full operation, thereby speeding up production and insuring a more perfect coating of tin plate than has heretofore been possible.

Still another object of my invention is the pro-' vision of an improved method of cleaning palm oil used in tinning machines which will materially increase the percentage of perfectly coated sheets.

Numerous other objects of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawings, discloses a pre-. ferred embodiment thereof.

Referring to the drawings:

Fig. 1 is a fragmentary, cross sectional view through a tinning machine, with a number of details of construction omitted.

Fig. 2 is a diagrammatic plan view of a series of tinning machines, connected by pipe lines with 50 an oil filtering device and an oil heating device.

In the manufacture of sheet metal containers which are used for the packing of a great variety of food and other products, millions of sheets of tin plate of standard size and weight are used up (or. 91 7o.2 v

as they come from the tinning mills cannot be' used for the manufacture of first class containers because of imperfections in their tin coating such as pin holes, black spots, and other undesirable defects.

I have found that most of these imperfect coat ings are caused by foreign. matter such as scruff, or iron-tin alloy particles, scale,'jrust, dirt, grit, .dried flux, which result from the coatingoperation, adhering to the sheet iron to be coated or 10 getting mixed with the molten tin and oil, thereby preventing a continuous, smooth, even coating of tin on both sides of the ferrous sheet metal.

I havealso found that most of this undesirable foreign matter is carried into the palm-oil which 15 is used in tinning machines and mixes with the oil, and that if the oil is continuous y purified by my improved method while the coating operation is going on, the percentage of defective tin plate due to the above mentioned causes can be sub- 20 stantially eliminated.

/ To illustrate my improved method ofpurifying palm oil or other suitable oil used in tin plate coating machines, I have shown across section of a simple form of tincoating machine in Fig. 1, 25 and in Fig. 2 I have shown a diagrammatic plan view of a series of such coating machines connected with an oil purifying device and aheating device by means of a system of pipe connections. 1

Referring to Fig. 1, my preferred illustration of a modern type of tin coating'machine comprises a compartment tank or tinning pot I I having end walls l2 and I3, side walls l4 and IS, a compartment wall I6, side walls I! and I8 opposite the 35 side walls l4 and I5, (see Fig. 2) and a bottom wall IS. The compartment wall It divides the tank ll into compartments A and-B; The wall It terminates at its lowerend a short distance from the bottom l9, thereby establishing a pas- 40 sageway between compartments A and B.

The tank is filled with molten tin 2D to a level 2| in compartment A and a slightly lowerlevel 22 in compartment B. A layer of molten flux 23 floats on top of the molten tin 20 in compartment 45' A and reachesa level 24. A body of oil 25, pref erably palm oil, floats on top .of the molten tin 2|] in compartment B, and reachesa level 25'. Palm oil or other suitable'oil is used in tin coat.- ing machines as a lubricant and to prevent the atmosphere from coming in contact with the fresh tin coating until the coating operation has been completed outside of the body of molten tin. The molten tin 20 and the bodies of flux and oil on top of the molten tin are maintained at a uniform temperature by suitable gas or electric heating devices (not shown).

When the flux, molten tin and oil are in properly heated condition, standard size sheets of iron 26 are fed down an incline 21 integral with the frame of the tank ll, through the layer of fiux 23 and the molten tin 20 into the bite of two pairs of feed rollers C and D which propel' the sheets of iron.along a guide rail 28 into the bite of two pairs of feeding out and compressing rollers E and F which are located above the level 22 of the molten tin and are immersed in the heated palm oil 25. The rollers E and F are of a length which is equal to or in excess of the width of the tin plate, and perform two functions, namely, they help to feed the sheet coated with tin out of the tinning machine and also compress the sheet so that any excess tin is squeezed 011 the two sides of the sheet. Some of this excess tin drops through the body of oil back into the'body of molten tin and some of it is carried up with the rollers and is wiped off the rollers by suitable wipers or brushes 29 secured in proper position by any suitable supporting means (not shown).

Fig. 2 illustrates a diagrammatic plan view of a series of tin coating machines, tinning'pots, or tanks ll, arranged in uniform line. ber of these machines may beincreased or decreased according to the volume of tin coating to be done and the available fioor space. Oil pipes are or may be arranged and combined with the pots and tanks as follows:A pipe 30 threadedly connected with an outlet hole 3| in the wall l3 leads from the body ,of oil in eachtinning pot l I to a main pipe formed of sections 3| The main pipe sections 3| run at right angles to the pipes 30 and are connected with the latter by means of elbow 32 and Ts 33. One end of a pump 34 of any suitable standard make has a threaded conwith one end of a force pump 44 of standard make whose other end is, in turn, connected with a section of a series of pipe sections 45 similar to the pipe sections 3| on the opposite side of the tanks l I, and running parallel with the same.

A transverse pipe 46 leads over-compartment A of each tank II at a sufficient height so as not to interfere with the feeding of the iron sheets 26 and makes connection with a threaded hole 41 in compartment wall l6 by means of an elbow 48 and a short piece of pipe 49. Connection between these pipes 46 and the main pipe sections 45 are made by means of Ts 50 and elbow The operation of my method of purifying the oil in tinningmachines is as follows:

Oil laden with impurities such as'have been enumerated above is withdrawn from the series of tanks ll through pipes 30- and 3| by means of pump 34 and forced through the filtering device 36 where impurities are removed from the oil. The purified oil is then forced out of the filtering device 36 into the heater 42 where it is heated to proper temperature. A second force pump 44 withdraws the purified and heated oil from the heater 42 and forces the same back into the compartments B of the tanks I I by means of the pipes 45 and 46. This withdrawalof impure oil from the tanks and the return of purified and The numat a substantially unifo heated oil back into the tanks takes place while the tinning machines are running at full speed so that there will be no interruption in the tinning operation.

The fiow of impure oil from the tanks ll 5, ,through outlets 3| and the return of the purified oil through the inlets 41 is continuous and can be so regulated by means of the pumps and associated devices not shown in detail, that a continuous circulation of purified oil in the direction of the arrows takes place and a uniform level of oil is maintained at all times in all of the tanks ll during the coating and oil purifying operations. The heating ofthe oil in heater 42 may in some cases not be necessary, and this step, in my improved method, may be omitted without departing from the spirit and scope of my invention.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may -b'e made in steps and their order of accomplishment of the process described without departing from the spirit and, scope of the invention or sacrificing all of its ma- 1 terial advantages, the process hereinbefore described being merely a preferred embodiment thereof.

I claim: a

1. The method of removing impurities from oil used in a tin coating machine, which comprises, transferring oil which contains impurities resulting from the tin coating operation, to a cleaning device, removing said impurities by means of said cleaning device, heating 'the purified oil and returning it'to said coating machine.

2. The method of removing impurities from oil used in a tin coating machine, which comprises, transferring oil which contains impurities resulting from the coating operation toafiltering device, removing said impurities by means of said filtering device, heating the purified oil and returning it to said coating machine.-

3. The method of removing impurities from oil used in a tin coating machine, which comprises, transferring oil which contains impurities result- 45 ing from the coating operation to a filtering device, removing said impurities by means of said device, heating said purified 'oil and returning it to said coating machine, said transferring and return of the oil being continuous and without substantially decreasing the level of the oil in said coating machine.

4. The method of removing impurities from oil used in tin coatingm'achines, w ch comprises, withdrawing oil which contains impurities resulting from the coating operation from a plurality of coating machines to a cleaning device, remov I ing said impurities by means of said device, heating the purified oila iid'returning itto said coating machines in ,a continuous uniform stream so as to maintain the oil in saidcoatingmachines level.

5. The method of rem ving impurities'from oil used in tin coating machines, which comprises, withdrawing oil which contains impurities result ing from the coating operation from a plurality of coating machines to a filtering machine by means of pipe lines, removing said impurities by means of said filtering machine, heating said purified oil to a temperature substantially equal.70 to the temperature maintained in said coating machines, and returning said purified and heated oil to said coating machines by means of pipe lines, said withdrawal, and return being effected in a continuous and uniform stream so as to 9. An apparatus for coating sheet metal with tin, comprising a tank for containing molten tin maintain a substantially uniform level of oil' insaid coating machines.

6. The method of removing impurities from palm oil or other suitable oil used in tin coating machines, which comprises, withdrawing palm oil which contains impurities resultingfrom the coating operation from a plurality of tin coating machines to a filtering device, removing said impurities by means of said device, heating the purified oil and returning it to said tin coatingpalm oil used in tin coating machines, which comprises,-withdrawing palm oil which contains impurities resulting from the tinfcoating operation from a pluralityof tin coating machines to a cleaning device by means of a pump, removing. said impurities from said oil by means of said device, heating said purified oil and pumping said purified and heated oil back into said tin coating machines.

and a bath of oil upon the molten tin, means outside said tank for filtering Said oil as the tinning of sheetsprogresses to remove impurities there- .5 from, means for heating the filtered oil, and means for circulating the oil under pressure from said tank and through said filtering means and heater .and back to said tank.

10. An apparatus for continuously coating 10' sheet metal with tin, comprising in' combina- 'tion: a series of tin coating machines each having compartments for molten tin and oil and adapted to receive the sheetmetal to be coated,

a filter, an oil withdrawal pipe leading from said 15 oil compartments to said filter, an oil supply pipe also connecting the oil compartments of said ma chines with said filter to provide continuous circulation of the oil through said compartments, oil

' pumping means disposed in said withdrawal pipe zo for forcing under pressure the oil from said compartments through said filter, the purified oil being conducted-by said supply pipe from said filter to said oil compartments prior to being again returned to said filter, and an oil heater 25 arranged to heat the oil to be returned to said oil compartments-,'said continuous circulation of oil taking place without interruption of the tin coating operations in said machines.

v 2 WILLIAM E. TAYLOR. 80 

